In recent years, increased attention has focused on the role of meibomian gland dysfunction in the pathogenesis of external eye disease, such as acne rosacea, seborrheic blepharitis, conjunctivitis, chalazia and contact lens wearing problems. External eye disease where meibomian gland dysfunction has been implicated are known to be significant causes of ocular morbidity in this country. We hypothesize that abnormalities of both structure and function of the meibomian glands are important in lid margin disease. We have an animal model of meibomian gland dysfunction (MGD) which will enable us to test this hypothesis over a three year period. Detailed study of this model is planned in order to determine the short-term and long-term natural history of MGD by detailed clinical examination, transilluminated biomicroscopy (assessment of meibomian gland morphology in vivo), microbiology, clinical histopathologic correlation, electron microscopy and biochemical analysis of lipid excretion. This study will be a collaborative effort involving clinical, morphologic, and biochemical techniques. Our long range goal is to study the effects of therapeutic intervention (e.g., tetracycline) on the progression of experimental MGD in order to determine the efficacy of present day therapy in the treatment of external eye disease associated with MGD.